Spring Boot with GraalVM

Known GraalVM Native Image limitations

General

Signed JARs (used for example in the Azure Java SDK) are not supported out of the box. See this comment on the spring-framework issue for the proposed workaround.
GraalVM with Truffle (Ruby,JavaScript) as a native image does not work with Spring applications because this disables inlining support.

Core container

Using beans defined as lambdas or instance suppliers with AOT/native is not yet supported (for example when using a functional router with WebFlux). You can track the related issue spring-framework#29555 where some workarounds are described.
Loading external resources using the "jar" protocol is not supported by default, as it’s not enabled by default. You can enable this in your build with the --enable-url-protocols=jar option with the native build tools build plugin.

Testing

Mockito is not supported yet, see #32195. You can disable tests which rely on Mockito with @DisabledInNativeImage.

Building Container Images

Paketo Buildpacks do not yet have official support for building images for ARM. Instructions for creating your own ARM-compatible builder are available. There are alternative builders available, too.

WebJars

WebJars are not recommended with native images since the webjars-locator-core dependency involves unsupported resource scanning at runtime, and since WebJars dependencies lead to the inclusion of unneeded resources from META-INF/resources/. Consider alternative approaches like directly shipping the required frontend resources in the web application, potentially by leveraging build plugins like the gradle-node-plugin for Gradle or the frontend-maven-plugin for Maven (see related blog post).

SQL

In-Memory Databases

HSQLDB is not supported in a native image. If you require an in-memory database, please use H2 instead.

Flyway

Automatic detection of Java migrations are not supported in native image, see #33458

Hibernate

Gradle projects written in Kotlin will fail with a ClassCastException when attempting to configure Hibernate’s bytecode enhancement. HHH-15707 is tracking the problem.

Native libraries needed on Linux / MacOS systems

If org.glassfish.jaxb:jaxb-runtime is used (for example, JPA / Hibernate depends on it), you’ll need to install the libfreetype library on your Linux or MacOS system. That’s because a class inside JAXB depends on javax.imageio, which will initialize the graphics subsystem.

Spring Web Services

Spring-WS does not support AOT and GraalVM Native at the moment.

Spring Cloud

Please see their dedicated document.

Further GraalVM tweaking

Spring Cloud Azure

To use Spring Cloud Azure with GraalVM, you’ll need to add the spring-cloud-azure-native-reachability dependency

Using tomcat-embed-programmatic

Motivation

tomcat-embed-programmatic is an experimental Tomcat dependency designed to lower the memory footprint. Using it produces smaller native images.

Maven

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
  <exclusions>
    <exclusion>
      <groupId>org.apache.tomcat.embed</groupId>
      <artifactId>tomcat-embed-core</artifactId>
    </exclusion>
    <exclusion>
      <groupId>org.apache.tomcat.embed</groupId>
      <artifactId>tomcat-embed-websocket</artifactId>
    </exclusion>
  </exclusions>
</dependency>
<dependency>
  <groupId>org.apache.tomcat.experimental</groupId>
  <artifactId>tomcat-embed-programmatic</artifactId>
  <version>${tomcat.version}</version>
</dependency>

Gradle

implementation('org.springframework.boot:spring-boot-starter-web') {
  exclude group: 'org.apache.tomcat.embed', module: 'tomcat-embed-core'
  exclude group: 'org.apache.tomcat.embed', module: 'tomcat-embed-websocket'
}
String tomcatVersion = dependencyManagement.importedProperties['tomcat.version']
implementation "org.apache.tomcat.experimental:tomcat-embed-programmatic:$tomcatVersion"